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Old 10-31-2022, 03:00 PM   #1
Toby740W
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Default DSM CAS + MS - Loss of RPM signal when hot

I'm losing all RPM signal to my MS but only when at operating temp for 10-15 min. Let the car cool for 15-30 min and its back.

I suspect CAS is getting flakey when warm, just curious if anyone has experienced this?
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Old 10-31-2022, 04:30 PM   #2
Harlard
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Is it an old CAS from a junkyard car?

Also, how is your wiring harness constructed?
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Old 10-31-2022, 06:48 PM   #3
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I did work on a car where the CAS was working and then flaked out a few weeks later. It was a junkyard CAS, with the cover painted a dirty gold/bronze. A replacement CAS fixed the issue.
http://forums.turbobricks.com/showthread.php?t=318596

Before replacement, do you have any high-speed logs of it cranking when bad? Do you have any noise filtering enabled (you shouldn't)? When it dies, does anything else in a normal MS log go bad, like Vbatt +12v or TPS?
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Old 10-31-2022, 06:57 PM   #4
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The reason that CASs fail is heat exposure as they are installed near the exhaust manifold in their original application.
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Old 11-01-2022, 10:40 AM   #5
Toby740W
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Older CAS for sure, you do bring up a good point about the original application. The wiring is not bad but could be better.

Seems I did not save a high-speed log but looking at the MS log when it quit running, nothing else looks abnormal to me (12v+ and TPS happy). I did notice a sync loss error code 17 right before the RPM fell off the cliff. I will try to reproduce it one more time and get a high-speed log. Tt seems these CAS are not as cheap as they use to be, what's the preferred option for a new OEM quality replacement? Did the hyundai parts prove to be usable?
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Old 11-01-2022, 12:18 PM   #6
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You could run a stock crank sensor so long as your signal conditioning circuit is better than MS's. Some people modify the intermediate shaft to get a cam signal using a Hall effect sensor. You could also use an EZK117 distributor to provide a cam position signal.
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